Small-size comb-line microstrip narrow BPF

Abstract

A small-size microstrip BPF is developed by using a high dielectric constant (E r = 92) substrate, shield-lines between coupled resonators to get smaller coupling coefficient and short microstrip-line resonators of comb-line type. The newly developed three stage BPF is designed and demonstrated at 1.2GHz. This BPF can be produced at low cost and is useful for portable radio equipment.

Planar lossy filters for satellite transponders

“…Generally, high Q resonators are physically larger and require the use of more expensive technology. For example, dielectric resonator filters can offer a very high quality factor [7], but their volume and cost is much higher than filters in microstrip technology [8]. It is shown in [9], that insertion losses (IL) are inversely proportional to the unloaded quality factor Qu.…”